Wavelength division multiplexing (WDM) is one technology that is envisioned to increase bandwidth capability and enable bi-directional communications in optical networks. In WDM networks, multiple data signals can be transmitted simultaneously between network elements (NEs) using a single fiber. Specifically, the individual signals may be assigned different transmission wavelengths so that they do not interfere or collide with each other. The path that the signal takes through the network is referred to as the lightpath. One type of WDM network, a wavelength switched optical network (WSON), seeks to switch the optical signals with fewer optical-electrical-optical (OEO) conversions along the lightpath, e.g. at the individual NEs, than existing optical networks. One of the challenges in implementing WSONs is the determination of the routing and wavelength assignment (RWA) for the various signals that are being transported through the network at any given time. To implement RWA, various NE related information can be forwarded from a Path Computation Client (PCC), such as a NE, and received and processed at a Path Computation Element (PCE). Such RWA information may include port wavelength restriction at the NE.